Pump.



N. W. THOMPSON & F..J. McGRAW.

- PUMP..

APPLICATION FILED JULY 2. 1917.

Patented Aug. 13,1918.

principal object of the invention is to pro-' tit bill

NELSON W. THOMPSON, OI OAKLAND, AND FRANK T. MGGRAW, OF MARTINEZ, CALI- FORNIA, ASSIG-NORS, BY MESNE ASSIGNMENTS, TO SHELL COMPANY OF CALIFORNIA, Cll!" SAN FRANCISCO, CALIFORNIA, A CORPORATION OF CALIFORNIA PUMP.

IMAM/INA.

Specification of Letters Patent.

Patented Aug. 13, IOTA.

Application filed July 2, 1917. Serial No. 178,269.

. dress is 6019 Hillegass avenue, Oakland,

Alameda county, California,) and the latter residing at Martinez, in the county of Contra Costa and State of California, (whose post-office address is P. O. Box 581, Mar tinez, Contra Costa county, California,) have invented a new and useful Pump, of which the following is a specification.

Our invention relates to pumps, and the vide a pump which may be used in conjunction with oil cracking apparatus.

It is common practice in the petroleum industry to subject oils to considerable temperatures and pressures for the purpose of changing their chemical characteristics, or more specifically for the purpose of lowering their boiling point and increasing their volatili-ty. When oils are subjected to the proper conditions to accomplish this considerable deposits of carbon often take place, and this carbon readily deposits and adheres to metalsurface s. It is often necessary in operation ofsuch systems to pump the residual of such cracking processes While still hot and while under considerable pressure. The ordinary forms of pumps are unsuited to this work as the valves thereof become clogged by carbon deposits and the pump' soon becomes inoperative. The greatest trouble in operating said pumps is found with the inlet valve.

The principal object of our invention is to provide a pump which is especially adapted to work in conjunction with the stills used in such cracking processes.

Further objects and. advantages will be made evident hereinafter.

Referring to the drawings, which are for illustrative purposes only:

Figure 1 is a plan view of apparatus adapted for this particular service.

Fig, 2 is an elevation, partly in section, on a plane represented by the line 2-2 of Fig. 1.

In the embodiment of our invention shown a in these drawings, a conical bottom 11 of a crackmg still shown connected by means of flanges 12 and 13 with an injector ring 14 and a pump casing 15. The pump casing 15 comprises walls inclosing an inlet opening 16 registering with an outlet opening '17 of the still 11,- and walls forming piston cylinders 18, which are coaxial with each other and at approximately right angles to the vertical axis of the still. Sliding in the cylinders 18 are pistons 19 which are aotuated through aisuitable piston rod 20 by any sort of suitable reciprocating mechanism,

not shown, the piston rod 20 passing through a stuffing box 21. Communicating with the ,"outer ends of each of the cylinders 18 is a pump outlet opening 22 which is provided with a ball valve 23 and a discharge flange 24. The discharge flanges 24 are connected to a common outlet pipe, not shown, through which the hot residuum may be forced back into the still 11 or may be delivered to any other suitable apparatus." Secured to the pistons 19 and extending up- Wardly through the openings 16 and 17 are stirring rods 30. These rods serve to break up any carbon deposited and prevent it from choking the openings 16 and 17. Connected into each of the outlet pipes above the valve 23 is a recirculating pipe 40, each of these pipes being provided with a valvejetl and being connected into the injector ring 141: on either side thereof. a

The method of operation of our invention is as follows:

The pistons "19 being reciprocated in the cylinders 18, the stirring rods are also reciprocated moving from side to side in the openings 16 and 17 and effectually preventing any accumulation of carbon therein. The pistons 19 form their own inlet valves, forcing residuum through the valves 23 on the pressure stroke and causing a slight vacuum under the valve 23 on the return strokefand this vacuum is immediatelyfilled with hot residuum as soon as the piston 19 reaches a point where the interior ofthe cylinders 18 and the opening 16 are in full communication with each other. The pistons 1.9 are run considerably faster than is necessary to handle the full capacity of the still 11, and the valves 41 are partially open allowing the residuum under pressure to be continuously forced through the pipes and the injector ring 14 into the opening 17. This rapid and continuous flow further titl' Itld Itlti tends to prevent any-deposits of carbon in the'opening 17.

We claim as our invention 1. In combination; a cracking still; a pump taking liquid from said still through an opening in the bottom of said still; stirring rods projecting into said opening; and meians by which said pump actuates said ro s,

2. In combination; a cracking still having a discharge opening therein; a pump taking liquid from said still through said opening; and pipe means connected to the pressure side of said pump and so arranged that oil from said pump is injected under pressure into said opening to prevent carbon deposits therein.

I 3. In combination; a cracking still having a discharge opening therein; a pump taking liquid from said still through said opening; stirring rods projecting into said opening; mechanism by which said pump actuates said stirring rods; and pipe means connected to the pressure side of said pump and so arranged that oil from said pump is injected 'under pressure into said opening to prevent carbon deposits therein.

4. In combination; a cracking still having a discharge opening therein; a pump casing having walls inclosing a pump inlet opening regis' ering with and forming a contin'uation of said discharge opening; walls forming two cylinders coaxial with each other and in open communication with said pump inlet opening; pistons moving in said cylinders; stirring means attached to said pistons and projecting through said pump inlet opening into said discharge opening; and a discharge valve in the end of each cylinder. 7

In testimony whereof, we have hereunto set our hands at the city and county of San Francisco, State of California, this 15th day of June, 1917.

NELSON W. THOMPSON.

FRANK J. MCGRAW. 

